The present invention relates to a hydraulically actuated door apparatus, and more particularly to a door system for use in connection with cages housing large primates.
The typical enclosed environment for housing large primates or other subjects includes a first relatively large area for allowing the animal sufficient room to move about, and a second, smaller area, such as a cage, for providing more security and covering for the animal. A door has been traditionally used to separate the two environments.
It is advantageous to have a door which will extend to the primate an opportunity to travel freely between the two environments. It is also advantageous, for both security and for maintaining the environment inside the cage, to have a door which the primate can operate, and which can be opened by the animal and closed automatically. It is also important that there be an overriding control of the door by the caretaker.
In the past, such doors have been manually operated by the caretaker. This, however, is time consuming for the keeper. Electrically operated doors have also been used but these doors typically raise at uneven speeds and experience has shown that young primates often get their heads caught in the door. Also, the movement of the closing door should exert as little force as possible and should also be as quiet as possible. While these objectives may be accomplished with sophisticated electronics, too often this option is foreclosed to cost conscious research labs, zoos and municipalities.
Therefore, there exists a need for a door for use between two environments which is safe, effective, easy to maintain and inexpensive to both build and operate.
There exists a further need for such a door which is controllable by the subject and which has overriding control by a caretaker.
Partition opening and closing mechanisms that include hydraulic components are disclosed in Mercier, U.S. Pat. No. 2,741,477; Bruehler, U.S. Pat. No. 4,621,451; and Allenson, U.S. Pat. No. 1,542,205.